We recently ran across an issue one of our customers was having with his 120/240VAC system. He had traveled to different marinas along the Florida coast and kept running into low voltage on his AC system. The issue was that some marinas were only providing 208VAC at their pedestals. This is a problem that only occurs in a boat plugging into 240VAC shore power and have an isolation transformer that takes the 240VAC and splits it into two 120VAC legs. He encountered this at 3 of the 10 marinas that he visited. We were able to remedy the problem by rewiring his existing isolation transformer and adding a breaker panel to control it. The customer wrote an article for the Mainship owners forum explaining what was involved and how the system works.
Below is a link to the article.